Continued
There are carnivorous, herbivorous and omnivorous species, but in a lot of species their favourite food is honeydew, which they milk from Aphids, which has a high sugar content. When an ant finds a food source it will lay a pheromone(scent) trail back to the nest, where it will communicate with other workers by tapping antennae and also giving some of the food from it's crop, these workers in turn will then be able to locate the food. So when you spill sugar or a sticky drink in your kitchen or living room now you know why suddenly there's lots of ants about.